diff --git a/lib/widgets/emoji_reaction.dart b/lib/widgets/emoji_reaction.dart
index ba7fc7a4a4e..2c63fef9c4b 100644
--- a/lib/widgets/emoji_reaction.dart
+++ b/lib/widgets/emoji_reaction.dart
@@ -153,6 +153,7 @@ class ReactionChip extends StatelessWidget {
                 //   which we learn about especially late).
                 final maxLabelWidth = (maxRowWidth - 6) * 0.75; // 6 is padding
 
+                final labelScaler = _labelTextScalerClamped(context);
                 return Row(
                   mainAxisSize: MainAxisSize.min,
                   crossAxisAlignment: CrossAxisAlignment.center,
@@ -168,9 +169,13 @@ class ReactionChip extends StatelessWidget {
                         constraints: BoxConstraints(maxWidth: maxLabelWidth),
                         child: Text(
                           textWidthBasis: TextWidthBasis.longestLine,
-                          textScaler: _labelTextScalerClamped(context),
+                          textScaler: labelScaler,
                           style: TextStyle(
                             fontSize: (14 * 0.90),
+                            letterSpacing: proportionalLetterSpacing(context,
+                              kButtonTextLetterSpacingProportion,
+                              baseFontSize: (14 * 0.90),
+                              textScaler: labelScaler),
                             height: 13 / (14 * 0.90),
                             color: labelColor,
                           ).merge(weightVariableTextStyle(context,
diff --git a/lib/widgets/message_list.dart b/lib/widgets/message_list.dart
index a102fb13e52..f3c8b63ba0c 100644
--- a/lib/widgets/message_list.dart
+++ b/lib/widgets/message_list.dart
@@ -484,8 +484,10 @@ class MarkAsReadWidget extends StatelessWidget {
                   // [zulipTypography]…
                   Theme.of(context).textTheme.labelLarge!
                   // …then clobber some attributes to follow Figma:
-                  .merge(const TextStyle(
+                  .merge(TextStyle(
                     fontSize: 18,
+                    letterSpacing: proportionalLetterSpacing(context,
+                      kButtonTextLetterSpacingProportion, baseFontSize: 18),
                     height: (23 / 18))
                   .merge(weightVariableTextStyle(context, wght: 400))),
                 shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(7)),
diff --git a/lib/widgets/text.dart b/lib/widgets/text.dart
index a3c82aceb97..d0fbea35461 100644
--- a/lib/widgets/text.dart
+++ b/lib/widgets/text.dart
@@ -40,6 +40,14 @@ Typography zulipTypography(BuildContext context) {
     result = _convertTextTheme(result, (maybeInputStyle, _) =>
       maybeInputStyle?.merge(const TextStyle(letterSpacing: 0)));
 
+    result = result.copyWith(
+      labelLarge: result.labelLarge!.copyWith(
+        fontSize: 14.0, // (should be unchanged; restated here for explicitness)
+        letterSpacing: proportionalLetterSpacing(context,
+          kButtonTextLetterSpacingProportion, baseFontSize: 14.0),
+      ),
+    );
+
     return result;
   }
 
@@ -167,6 +175,8 @@ final TextStyle kMonospaceTextStyle = TextStyle(
   inherit: true,
 );
 
+const kButtonTextLetterSpacingProportion = 0.01;
+
 /// A mergeable [TextStyle] to use when the preferred font has a "wght" axis.
 ///
 /// Some variable fonts can be controlled on a "wght" axis.
diff --git a/test/flutter_checks.dart b/test/flutter_checks.dart
index bc7e9d83a70..20a38225dc5 100644
--- a/test/flutter_checks.dart
+++ b/test/flutter_checks.dart
@@ -65,6 +65,7 @@ extension TextFieldChecks on Subject<TextField> {
 
 extension TextStyleChecks on Subject<TextStyle> {
   Subject<bool> get inherit => has((t) => t.inherit, 'inherit');
+  Subject<double?> get fontSize => has((t) => t.fontSize, 'fontSize');
   Subject<FontWeight?> get fontWeight => has((t) => t.fontWeight, 'fontWeight');
   Subject<double?> get letterSpacing => has((t) => t.letterSpacing, 'letterSpacing');
   Subject<List<FontVariation>?> get fontVariations => has((t) => t.fontVariations, 'fontVariations');
diff --git a/test/widgets/text_test.dart b/test/widgets/text_test.dart
index 9fb03b4bf9b..e4e683520f8 100644
--- a/test/widgets/text_test.dart
+++ b/test/widgets/text_test.dart
@@ -46,11 +46,14 @@ void main() {
       });
     }
 
-    testWidgets('zero letter spacing', (tester) async {
+    testWidgets('letter spacing', (tester) async {
       check(await getZulipTypography(tester, platformRequestsBold: false))
         ..englishLike.bodyMedium.isNotNull().letterSpacing.equals(0)
+        ..englishLike.labelLarge.isNotNull().letterSpacing.equals(0.14)
         ..dense.bodyMedium.isNotNull().letterSpacing.equals(0)
-        ..tall.bodyMedium.isNotNull().letterSpacing.equals(0);
+        ..dense.labelLarge.isNotNull().letterSpacing.equals(0.14)
+        ..tall.bodyMedium.isNotNull().letterSpacing.equals(0)
+        ..tall.labelLarge.isNotNull().letterSpacing.equals(0.14);
     });
 
     test('Typography has the assumed fields', () {
diff --git a/test/widgets/theme_test.dart b/test/widgets/theme_test.dart
new file mode 100644
index 00000000000..8ba10c45282
--- /dev/null
+++ b/test/widgets/theme_test.dart
@@ -0,0 +1,78 @@
+import 'package:checks/checks.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:zulip/widgets/text.dart';
+import 'package:zulip/widgets/theme.dart';
+
+import '../flutter_checks.dart';
+
+void main() {
+  group('button text size and letter spacing', () {
+    Future<void> doCheck(
+      String description, {
+      required Widget Function(BuildContext context, String text) buttonBuilder,
+      double? ambientTextScaleFactor,
+    }) async {
+      testWidgets(description, (WidgetTester tester) async {
+        if (ambientTextScaleFactor != null) {
+          tester.platformDispatcher.textScaleFactorTestValue = ambientTextScaleFactor;
+          addTearDown(tester.platformDispatcher.clearTextScaleFactorTestValue);
+        }
+        const buttonText = 'Zulip';
+        double? expectedFontSize;
+        double? expectedLetterSpacing;
+        await tester.pumpWidget(
+          Builder(builder: (context) => MaterialApp(
+            theme: zulipThemeData(context),
+            home: Builder(builder: (context) {
+              expectedFontSize = Theme.of(context).textTheme.labelLarge!.fontSize!;
+              expectedLetterSpacing = proportionalLetterSpacing(context,
+                0.01, baseFontSize: expectedFontSize!);
+              return Builder(builder: (context) =>
+                buttonBuilder(context, buttonText));
+            }))));
+
+        final text = tester.renderObject<RenderParagraph>(find.text(buttonText)).text;
+        check(text.style!)
+          ..fontSize.equals(expectedFontSize)
+          ..letterSpacing.equals(expectedLetterSpacing);
+      });
+    }
+
+    doCheck('with device text size adjusted',
+      ambientTextScaleFactor: 2.0,
+      buttonBuilder: (context, text) => ElevatedButton(onPressed: () {},
+        child: Text(text)));
+
+    doCheck('ElevatedButton',
+      buttonBuilder: (context, text) => ElevatedButton(onPressed: () {},
+        child: Text(text)));
+
+    doCheck('FilledButton',
+      buttonBuilder: (context, text) => FilledButton(onPressed: () {},
+        child: Text(text)));
+
+    // IconButton can't have text; skip
+
+    doCheck('MenuItemButton',
+      buttonBuilder: (context, text) => MenuItemButton(onPressed: () {},
+        child: Text(text)));
+
+    doCheck('SubmenuButton',
+      buttonBuilder: (context, text) => SubmenuButton(menuChildren: const [],
+        child: Text(text)));
+
+    doCheck('OutlinedButton',
+      buttonBuilder: (context, text) => OutlinedButton(onPressed: () {},
+        child: Text(text)));
+
+    doCheck('SegmentedButton',
+      buttonBuilder: (context, text) => SegmentedButton(selected: const {1},
+        segments: [ButtonSegment(value: 1, label: Text(text))]));
+
+    doCheck('TextButton',
+      buttonBuilder: (context, text) => TextButton(onPressed: () {},
+        child: Text(text)));
+  });
+}